The present invention relates to a hydraulically damping elastomeric bearing suitable for mountings in a motor vehicle.
German Published Patent Application No. 198 07 949 describes an elastomeric bearing, in which an elastic block, for example, made of an elastic plastic or rubber, is arranged between an outer sleeve and an inner sleeve coaxial thereto. With the aid of this block, an elastic connection between the outer sleeve and the inner sleeve is made, which allows relative movements between the sleeves. The elastomeric bearing also has two chambers which are filled with a liquid damping medium and communicate with one another via a throttle duct. Elastomeric bearings of this type are used in order to mount a vibrating assembly on a non-vibrating holding device. The elastomeric bearings serve in this context for vibration insulation or vibration damping. For example, elastomeric bearings of this type are used in vehicle construction, in order to mount vehicle axles, a transmission or an engine on the vehicle body. In this case, one of the sleeves is connected to the vibrating assembly, whereas the other sleeve is coupled to the non-vibrating holding device. The vibrations of the assembly result in relative movements between the sleeves which reduce the volume of one chamber and simultaneously increase the volume of the other chamber. At the same time, the liquid damping medium is exchanged correspondingly between the chambers via the throttle duct. The throttling action of the throttle duct results in a damping of the relative movement and therefore in a damping of the vibrations capable of being transmitted between the sleeves.
Conventional elastomeric bearings have a working direction dependent on the application because of the selected arrangement of the chambers. Thus, a reduction in volume of one chamber with a simultaneous increase in volume of the other chamber is possible only in the case of those relative movements between the sleeves which have a direction component arranged parallel to the working direction. A conventional elastomeric bearing can accordingly damp hydraulically only those loads or vibrations which have a direction component arranged parallel to the working direction. In some applications of such elastomeric bearings, particularly in vehicle construction, however, different loads with different loading directions may occur. For example, on a vehicle, propulsive forces and braking forces, impacts and wheel-load changes in different directions may act on the respective elastomeric bearing.
It is an object of the present invention to provide an elastomeric bearing, in which a damping action may be achieved in a plurality of different directions.
The above and other beneficial objects of the present invention are achieved by providing an elastomeric bearing as described herein. In one example embodiment of the present invention, a plurality of chambers are arranged in the elastomeric bearing and are connected to one another via corresponding throttle ducts so that two intersecting directions of movement are ensured and so that relative adjustment between the sleeves reduces the volume in at least one of the chambers and increases the volume in another chamber coupled thereto. Vibration damping may thereby be achieved for all directions of movement which are in a plane spanned by the intersecting directions of movement or axes.
According to an example embodiment of the present invention, each chamber which is arranged on a first side of the first axis and on a first side of the second axis may communicate, via a first of the throttle ducts, with a second chamber which is arranged on the first side of the first axis and on a second side of the second axis and, via a second of the throttle ducts, with a chamber which is arranged on a second side of the first axis and on the first side of the second axis. It is possible, by virtue of this arrangement of the chambers and throttle ducts, for one and the same chamber to be capable of being compressed in the two directions of movement arranged parallel to the axes. Furthermore, in such an example embodiment, it is possible to provide the first throttle duct and the second throttle duct with different throttling resistances, so that the damping action is more pronounced in the direction of one axis than in the direction of the other axis.
In connection with the present invention, the term xe2x80x9con this sidexe2x80x9d describes a position on one side, whilst the term xe2x80x9con that sidexe2x80x9d denotes a position on the other side.
According to an example embodiment of the present invention, one of the axes may be arranged coaxially to the sleeves of the elastomeric bearing. Axial loads on the elastomeric bearing are damped correspondingly.
In another example embodiment of the present invention, the inner sleeve of the elastomeric bearing may include at least one axial end portion, the outer contour of which includes an outside diameter increasing axially outwardly. By virtue of this arrangement, the inner sleeve may be fastened more effectively to a component to be connected thereto.
The outer contour of the axial end portion may delimit at least one of the chambers, thus resulting in intensive support and interaction between the respective chamber and the inner sleeve.
The features mentioned above and those explained below may be used not only in the combination specified but also in other combinations or alone, without departing from the scope of the present invention.